What are the effects of gravity on an object's acceleration?

Gravity causes an object to accelerate towards the centre of the Earth at a rate of approximately 9.8 m/s².

Gravity is a force that attracts two objects towards each other. In the context of Earth, it's the force that pulls objects towards the centre of the planet. This force of attraction causes an object to accelerate, or increase its speed, as it falls towards the Earth. This acceleration due to gravity is approximately 9.8 m/s², meaning that for every second an object is falling, its speed increases by about 9.8 metres per second.

This acceleration is constant for all objects near the Earth's surface, regardless of their mass. This principle, known as the equivalence principle, was famously demonstrated by Galileo who dropped two balls of different masses from the Leaning Tower of Pisa and found that they hit the ground at the same time. This is because the force of gravity is proportional to the mass of the object, so a heavier object experiences a greater gravitational force, but it also has more inertia (resistance to change in motion), so it accelerates at the same rate as a lighter object.

However, this acceleration can be affected by other factors such as air resistance. As an object falls, it pushes against the air molecules in its path, creating a force that opposes its motion. This force, known as drag, increases with the object's speed, so as the object accelerates due to gravity, it also experiences increasing air resistance. Eventually, the object reaches a speed where the force of gravity pulling it down is balanced by the air resistance pushing it up, and it stops accelerating. This speed is known as the terminal velocity.

In summary, gravity causes an object to accelerate towards the Earth at a rate of approximately 9.8 m/s², but this acceleration can be affected by factors such as air resistance.